Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Hyperdoping silicon with chalcogen atoms is a topic of increasing interest due to the strong sub-band gap absorption, which can be exploited to develop infrared photodectectors and intermediate band solar cells [1-3]. In our work, tellurium-hyperdoped Si layers have been fabricated by ion implantation followed by either millisecond flash lamp annealing (FLA) or nanosecond pulsed-laser melting (PLM). The electrical conduction and magnetoresistance of Te-hyperdoped Si are investigated at magnetic fields up to 5 T and temperatures ranging from 2 K to 300 K. With increasing Te concentration, an insulator-to-metal transition is observed although Te introduces a deep donor level (around 300–400 meV) below the Si conduction band. Moreover, the temperature-dependent conductivity measured at zero magnetic field shows that the charge transport is associated with variable-range hopping (VRH) at low temperatures, which scales as δ(T)=δ0 exp[-(T0/T)s] (S=1/4 or 1/2). In addition negative magnetoresistance is observed at low magnetic field, turning positive at B around 0.9 T.